Wound treatment apparatus employing reduced pressure

ABSTRACT

A method for stimulating new tissue growth is provided in which a limb is introduced into an interior portion of an outer cover. A porous component is applied to at least a portion of the limb within the outer cover. An opening through which the limb was introduced is sealed, and a negative pressure is applied to the interior portion to stimulate new tissue growth.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/009,294, filed Jun. 6, 2002, which was the National Stage ofInternational Application No. PCT/GB00/01566, filed Apr. 20, 2000, whichclaims the benefit of United Kingdom Application No. 9909301 5, filedApr. 22, 1999. Priority is claimed to all of the above-mentionedapplications, and each application is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for the healing of woundsand more particularly to preventing progression of partial-thicknessburns.

2. Description of Related Art

Where a person suffers a burn, the dermal and epidermal layers in theregion of the wound are damaged. Closure of the resulting wound isimportant to prevent loss of body fluids and invasion bymicro-organisms. In the case of a partial-thickness burn, epithelial andsubcutaneous tissue adjacent to the wound will migrate outwards andeventually grow new tissue over the wound. A wide array of woundcoverings has been developed to expedite wound closure and allow thenatural processes of repairing the damaged tissue to proceed.

The prognosis of a wound caused by a burn depends on the severity of theinjury and particularly the depth of the burn. In general, apartial-thickness burn will heal more quickly and with lesscomplications than a deeply penetrating burn. It has been observed thatpartial-thickness burns often deteriorate and become more serious,deeper burns, if not treated promptly after incurring the burn injury.

The hands more often suffer burn injuries than other parts of the body.Probably, this is due to the natural reaction of attempting to protectthe face with the hands and, in many cases, the burn injury is to theback of the hands. Other parts of the body which more frequently sufferburns may be the arms, feet and legs.

The present invention seeks to provide apparatus for treating injuriesto a part of the body, especially injuries caused by burns.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided an apparatusfor stimulating healing of wounds which comprises an envelope forreceiving an affected part of the body, said envelope including asubstantially air-tight cover and a porous pad within the cover, saidcover being adapted to contact the wound surface, and connection meansfor connecting the interior of the envelope to a source of negativepressure.

By substantially “air-tight” cover is meant one which is sufficientlyair-tight that by applying suction to the porous pad, a pressure belowambient can be maintained within the envelope. It is not, however,necessary for the material of the envelope to be totally air occlusive.

It has been found that when negative pressure therapy using theapparatus of the invention is applied to a burn within a relativelyshort time of incurring the injury (e.g. within about 12 hours), notonly is the rate of healing improved but progression of apartial-thickness burn to a deeper injury is arrested.

In one embodiment, the apparatus of the invention, the envelopecomprises a glove, sleeve or sock. For example, the apparatus mayinclude a glove formed from a flexible plastics or rubber foam which iscontained within a cover of low air-porosity. Typically, the flexibleplastics foam is a polyurethane or polyvinyl alcohol (PVA) foam havingintercommunicating cells or a combination of such foams, e.g. as alaminate. In such a laminate, the PVA layer may be adjacent the wound.

In another embodiment of the present invention, a method for stimulatingnew tissue growth is provided. A limb is introduced into an interiorportion of an outer cover, and a porous component is applied to at leasta portion of the limb within the outer cover. An opening through whichthe limb was introduced is sealed, and a negative pressure is applied tothe interior portion to stimulate new tissue growth.

Other objects, features, and advantages of the present invention willbecome apparent with reference to the drawings and detailed descriptionthat follow.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features of the present application will become apparent fromthe following description and accompanying drawings, in which:

FIG. 1 is an exploded perspective view of the porous pad;

FIG. 2 is a perspective view when the porous pad is assembled together;

FIG. 3 is a perspective view of the porous pad within its cover;

FIG. 4 a to 4 d show various views of a connector for pneumaticallyconnecting the porous pad to a source of negative pressure; and

FIG. 5 is a plan view of a modified cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration specific preferredembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is understood that other embodiments maybe utilized and that logical structural, mechanical, electrical, andchemical changes may be made without departing from the spirit or scopeof the invention. To avoid detail not necessary to enable those skilledin the art to practice the invention, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is defined only by the appended claims.

The embodiment shown in the accompanying drawings is designed for use intreating burns to the hand, but it will be appreciated that variousappropriate modifications are possible for treating burns to other partsof the body, such as feet and other extremities, within the scope of theinvention.

FIGS. 1, 2 and 3 show apparatus (10) for treating wounds to the handscomprising a porous pad having a lower base (22), a middle section (24)and an upper section (26) incorporated within a cover (12) of low airporosity. The porous pad is in the form of a glove or mitten and may beconstructed by fixing the upper section (26) to the base (22) whileretaining the middle section (24) within the cavity so formed.Typically, the porous pad is a reticulated plastics foam, and may beformed by gluing or welding the separate sections together. When placedinside the pad, the hand is held in place with fingers spread byfinger-separators (25) and V-cut type grooves (14). As shown in FIGS. 2and 3, the foam may be shaped to provide for a separate supportingcompartment (27) for the thumb to aid the attainment of the optimumpositions of the fingers and thumb for healing. However, this is notessential. The pad is preferably made from a reticulated foam such aspolyurethane as described in PCT application WO 96/05873,polyvinylalcohol foam or a combination thereof.

FIG. 3 shows the assembled pad after insertion into a cover (12). Cover(12) is an envelope formed from air-impermeable sheet material, e.g.polyurethane or polyolefin film, and is sized to encompass theglove-shaped porous pad. The distal end of the cover (12) has a largeopening (not shown) which is closable by an easily re-sealable means (4)such as a zip-type seal used on food bags. The proximal end (8) includesa substantially impermeable pressure-sensitive acrylic resin adhesive(9), the underside of which is secured as an air-tight seal to thepatient's skin. The proximal end (8) may be coated on its inner surfacewith a pressure-sensitive acrylic resin adhesive (9) in order to sealthe cover to the patient's skin, e.g. at the wrist or lower arm.Alternatively, the proximal end (8) may be sealed to the patient's wristwith a separate piece of adhesive tape, such as a polyurethane filmcoated with a pressure-sensitive adhesive. The proximal end (8) is openand is tapered as shown. By providing a taper, the proximal end can becut to a size such that the opening will fit snugly around the patient'swrist. Attached to the cover (12) in the region of a central part of theporous pad is a connector (100). Connector (100) may be attached to thecover by adhesive.

FIG. 5 is a plan view of a cover similar to cover (12) shown in FIG. 3.The same reference numerals are used to indicate corresponding parts.The cover shown in FIG. 5 differs from that shown in FIG. 3 in that theend (8) for attachment at the patient's wrist has a somewhat largertaper and is designed so that the end can be trimmed to suit thepatient. The connector (100) has a generally circular flange (101) whoseunderside face (i.e. the face which in use contacts the foam page 20) isformed with small projecting buttons. The construction of this aspect ofthe connector is as described in GB Patent Application No. 2,333,965.Instead of using a zip lock seal, a seal of the “Velcro” type can beused. In this embodiment, a zip lock seal (4) is formed frompolyethylene and this is joined to the rest of the cover, which isformed from polyurethane, by adhesive tape.

FIGS. 4 a to 4 d show various views of the connector (100) and it willbe seen that it comprises a molded plastics flange portion (101) andsuction port having a centrally positioned spout (102) and aperture(106). The connector (100) is firmly attached to the cover by anadhesive. The spout extends through a hole cut in the cover and theupper surface of the flange (101) is bonded with adhesive to the cover(12). The spout (102) is sized to accept as a closely sliding fit, theend of a single or multi-lumen tube (30) (FIG. 3) which emerges frombeneath the wound cover (12). Tube (30) may be constructed as describedin co-pending patent application WO 97/18007. Where a multi-lumen tubeis used, one lumen can be used for measuring the pressure at the burnsite. It is also within the scope of this invention to irrigate the burnor other wound through one of the lumens or via a separate connector tothe foam pad. The connector or connectors can be used to introducedrugs, e.g. antibiotics, to the wound site. The cover drape (12) ispreferably made from a flexible film of low air permeability such aspolyurethane and may include a protective layer of polyethylene.Suitable materials are described in GB Patent Application No. 2,333,965.

In use, the hand of a patient having a burn injury is introduced intothe outer cover (12) via the end (8). Re-sealable opening (4) may thenbe opened and folded back to expose the injured hand. The hand is thenintroduced into the porous pad which may be pre-assembled or assembledin situ around the injured hand. In the latter case, it may beconvenient to fix the upper section (26) to the lower base (24) bysuturing or stapling, rather than gluing or welding the foam. With thefoam pad in place encompassing the injured hand, the cover (12) is drawnover the porous pad and the opening (4) re-sealed. Spout (102) is thenconnected by a tube to a suction pump, e.g. using the techniquedescribed in WO 97/108007. Pulsed, intermittent or continuous negativepressure may be applied to the patient's hand in accordance with aprogram which may be controlled automatically by a control deviceassociated with the pump as described in our above patent application.Negative pressure therapy using the apparatus of the invention has beenfound to stimulate healing of burns and to reduce the progression ofcell death beneath a burn injury. Also, by improving blood flow to thewound area, infection is controlled and granulation of the wound isstimulated.

One additional beneficial effect of therapy using the apparatus of thisinvention is that during therapy, the hand is held firmly in ahalf-closed position, which is the optimum position for promotion ofhealing. This can be further encouraged by the introduction of a rigidor semi-rigid splint, e.g. of plastics, which is formed or molded intothe desired shape, the collapsed dressing being strapped to the splintduring or after application of the suction, so that the desired healingposition can be maintained after release of the suction.

The suction pump is perfectly controlled by control means including apressure transducer for monitoring pressure at the wound site asdescribed in our above PCT application. A timer device may also beassociated with the pump to provide on/off operation if necessary atselected intervals. The apparatus may also include a canister locatedbetween the porous pad and the pump to collect wound exudate. Typically,the pump is a diaphragm pump but other types of pumps and equivalentcomponents, such as vacuum bottles may be substituted. The apparatus mayalso be used with a wall suction source as described in GB PatentApplication No. 2,342,584.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation. Although the present inventionrelates mainly to partial-thickness burns, it is understood that thepresent invention maybe used with open wounds as well as a possibletreatment of pressure sores.

It should be apparent from the foregoing that an invention havingsignificant advantages has been provided. While the invention is shownin only a few of its forms, it is not just limited but is susceptible tovarious changes and modifications without departing from the spiritthereof.

1. A method for stimulating new tissue growth, comprising: introducing alimb of a patient into an interior portion of an outer cover via anopening of the outer cover; applying a porous component to at least aportion of the limb within the outer cover; sealing the opening; andstimulating new tissue growth by applying a negative pressure to theinterior portion of the outer cover.
 2. The method according to claim 1,wherein applying the negative pressure further comprises applying anintermittent negative pressure to the limb sealed in the outer cover. 3.The method according to claim 1, wherein applying the negative pressurefurther comprises applying a continuous negative pressure to the limbsealed in the outer cover.
 4. The method according to claim 1, furthercomprising automatically controlling the application of negativepressure using a control device operably associated with a pump.
 5. Themethod according to claim 1, further comprising: unsealing a secondopening; exposing the limb through the unsealed second opening to applythe porous component to the limb; and resealing the second opening. 6.The method according to claim 5, wherein unsealing further comprisesunsealing a zip-type seal.
 7. The method according to claim 1, whereinapplying a porous component further comprises applying a glove-shapedporous component.
 8. The method according to claim 1, wherein: the limbincludes a hand and wrist of the patient; and sealing the open endincludes sealing the open end to the wrist of the patient.
 9. The methodaccording to claim 1, wherein introducing the limb of the patient to theouter cover further comprises introducing the limb to a substantiallyair-tight outer cover.
 10. The method according to claim 1, whereinapplying the porous component to the limb includes applying the porouscomponent to a hand of the limb while the hand is in at least apartially-closed position.
 11. The method according to claim 1, whereinapplying a porous component includes applying a porous component formedof a reticulated foam.
 12. The method according to claim 1, furthercomprising collecting wound exudates within a canister located betweenthe porous component and a pump used to apply the negative pressure.